Method and apparatus for employing stored content at receivers to improve efficiency of broadcast system bandwidth use

ABSTRACT

The invention relates generally to a receiver unit in a digital broadcast system for receiving a broadcast signal comprising content segments and control data, and generating an output signal using the content segments and previously stored content segments. The previously stored content segments are retrieved from a local memory device using the control data and inserted among the received content segments.

This application is a continuation of U.S. application Ser. No.11/553,398, filed Oct. 26, 2006, which is a continuation of U.S. patentapplication Ser. No. 09/695,226, Filed Oct. 25, 2000 (now issued as U.S.Pat. No. 7,180,917), the contents of both applications beingincorporated herein by reference.

CROSS REFERENCE TO RELATED APPLICATIONS

Related subject matter is disclosed and claimed in co-owned U.S. Pat.Nos. 6,876,835, 6,834,156, 6,686,880 and 6,564,003; in co-pending U.S.patent application Ser. No. 09/695,228 filed by Paul D. Marko et al onOct. 25, 2000; and in co-pending U.S. patent application Ser. No.11/379,040, filed by Hien D. Ma et al on Apr. 17, 2006; all of saidapplications and patents being expressly incorporated herein byreference.

FIELD OF THE INVENTION

The invention relates generally to an apparatus and method for reducingthe bandwidth used in a digital broadcast system to provide programcontent to a receiver unit.

BACKGROUND OF THE INVENTION

Satellite digital audio radio service (SDARS), a satellite broadcastservice established by the U.S. Federal Communications Commission (FCC),has been proposed using satellite transmission of digital audio programsto radio receivers. The radio receivers can be stationary receivers(i.e., with a receiver antenna pointed for optimal line of sight (LOS)reception from a satellite) or mobile receivers (e.g., a receiver thatis hand-carried by a user or is mounted in a vehicle).

The type of content which can be distributed in an SDARS system or asimilar digital broadcast system typically includes audio programs suchas music recordings, news programs and talk shows, among other programs,and advertisements. A digital broadcast also typically comprisesdialogue segments from a broadcast channel host or other program hostwhich occur between the audio programs and advertisements presented on abroadcast channel.

A significant amount of the content that is to be broadcast ispredetermined prior to transmission such as popular songs. Radiostations, for example, frequently use play lists to determine how oftena selected number of songs, which are identified as being most popularat a given point in time, are to be broadcast. Popular songs and otherprograms which can be repeated on a broadcast channel are in contrast to“live” commentary provided by a broadcast channel host, talk show hostor other commentator, for example.

Since bandwidth in a digital broadcast system is limited and valuable,efficient use of the bandwidth is desirable. A need therefore exists fora digital broadcast system wherein content is provided in a broadcastsignal in an optimal manner to use bandwidth as efficiently as possible.

SUMMARY OF THE INVENTION

The above described disadvantage is overcome and a number of advantagesare realized by a digital broadcast system wherein receivers areprovided with local storage devices for storing selected content (e.g.,audio programs). The broadcast signal employed by the digital broadcastsystem comprises dialogue segments, content segment identifierscorresponding to content that has been previously stored at the localstorage devices, and control data. The receivers are configured toreceive the broadcast signal and to generate an output signal forplayback via a loudspeaker, for example. The output signal is generatedby accessing and retrieving from the local storage device thosepreviously stored content segments identified in the broadcast signal.The retrieved segments are inserted in the output signal between thedialogue segments in accordance with the control data.

In accordance with another aspect of the present invention, thereceivers are provided with a processing device and a multiplexingdevice operable to receive control signals generated by the processingdevice in response to the control data and content segment identifiersprovided in the received broadcast signal. The multiplexing device thenassembles the output signal using the live segments in the broadcastsignal and by inserting the retrieved segments from the local storagedevice when instructed to do so via the processing device.

In accordance with yet another aspect of the present invention, thebroadcast signal comprises progress information relating to the durationof the previously stored segments identified in the broadcast signal forinsertion into an output signal by a receiver. The processing device isprogrammable to generate control signals in response to the progressinformation to establish timing for inserting selected, stored contentsegments into the output signal among the live broadcast segments.

In accordance with still yet another aspect of the present invention,the content segments stored in the local storage devices can be deletedor replaced with different segments (e.g., updated versions of storedsegments), and new content segments added to the storage device, viadifferent methods. For example, new content can be downloaded to thelocal storage device from a portable storage device, or transmitted tothe local storage device via wireline or wireless communication link, aswell as commands to the local storage device to delete or updatepreviously stored segments.

In accordance with the present invention, an apparatus for generating anoutput signal from a broadcast signal in a digital broadcast system isprovided which comprises (1) a memory device for storing predefinedcontent segments; (2) a receiver for receiving the broadcast signal, thebroadcast signal comprising content segments and control data providedamong the content segments to indicate where the predefined contentsegments are to be inserted by the apparatus, the receiver beingoperable to extract the content segments and the control data from thebroadcast signal; (3) an output device for playing back the outputsignal; (4) a processing device configured to receive the control datafrom the receiver and to generate a control signal used by the memorydevice to retrieve selected ones of the predefined content segments inaccordance with the control data; and (5) a multiplexer configured toreceive as inputs the control signal generated by the processing device,the content segments from the receiver and the selected predefinedcontent segments. The multiplexer generates the output signal using thecontent segments received by the receiver and inserting the predefinedcontent segments among the content segments in accordance with thecontrol data.

BRIEF DESCRIPTION OF DRAWINGS

The various aspects, advantages and novel features of the presentinvention will be more readily comprehended from the following detaileddescription when read in conjunction with the appended drawings, inwhich:

FIG. 1 illustrates an SDARS system constructed in accordance with anembodiment of the present invention;

FIG. 2 illustrates an exemplary radio broadcast transmission;

FIGS. 3A, 3B and 3C illustrate, respectively, an exemplary radiobroadcast transmission, stored content, and a receiver output signalgenerated in accordance with an embodiment of the present invention;

FIGS. 4A, 4B, 4C and 4D relative instantaneous bandwidth requirementsfor an exemplary broadcast transmission and a broadcast transmissiongenerated in accordance with the present invention; and

FIG. 5 is a block diagram of a receiver constructed in accordance withan embodiment of the present invention.

Throughout the drawing figures, like reference numerals will beunderstood to refer to like parts and components.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 depicts a satellite broadcast system 10 which comprises at leastone geostationary satellite 12, for example, for line of sight (LOS)satellite signal reception at receiver units indicated generally at 14.The satellite broadcast system 10 can be used for SDARS, for example.Another geostationary satellite 16 at a different orbital position isprovided for diversity purposes. One or more terrestrial repeaters 17can be provided to repeat satellite signals from one of the satellitesin geographic areas where LOS reception is obscured by tall buildings,hills and other obstructions. It is to be understood that differentnumbers of satellites can be used, and satellites in other types oforbits can be used. Alternatively, a broadcast signals can be sent usingonly a terrestrial transmission system.

As illustrated in FIG. 1, a receiver unit 14 can be configured forstationary use (e.g., on a subscriber's premises), or mobile use (e.g.,portable use or mobile use in a vehicle), or both. A control center 18is provided for telemetry, tracking and control of the satellites 12 and16. A programming center 20 is provided to generate and transmit acomposite data stream via the satellites 12 and 16 which comprises aplurality of payload channels. One of the payload channels 30 isdepicted in FIG. 2 for illustrative purposes. The system 10 canbroadcast a composite data stream generated, for example, bymultiplexing a plurality of payload channels 30. The receivers aretherefore configured to demultiplex a received composite data stream toplayback a selected one of the payload channels.

The programming center 20 is configured to obtain content from differentsources and providers which can comprise both analog and digitalinformation such as audio, video, data, program label information,auxiliary information, and so on. For example, the programming center 20can provide SDARS having on the order of 100 different program channelsto transmit different types of music programs (e.g., jazz, classical,rock, religious, country, and so on) and news programs (e.g., regional,national, political, financial and sports). The SDARS can also provideemergency information, travel advisory information, educationalprograms, and the like.

The types of content to be provided in a payload channel is determinedmanually or automatically via a computer, based on contractual andfinancial arrangements with information providers, and demographic andfinancial decisions determining the types of programming to be providedvia the programming center 20. In addition, a payload channel 30 cancomprise plural service components to provide a plurality of differentservices. For example, a number of service components in a payloadchannel can be related to the same service and can include an audiocomponent and a video and/or a digital data stream comprising auxiliaryinformation, or another audio component to insert advertisinginformation relating to the audio or video program.

With continued reference to FIG. 2, an exemplary payload channel 30 isshown which provides a radio broadcast transmission to the receivers 14.The radio broadcast transmission comprises a number of content segmentscorresponding to live talk 32 by a program channel host (e.g., discjockey), prerecorded commercials 34 and prerecorded musical selections36. In accordance with the present invention, receivers 14 areconfigured to access and playback locally stored content segments suchas prerecorded commercials 34 and musical selections 36 to reduce theamount of bandwidth required for a radio broadcast transmission, forexample. The locally stored content segments can include prerecordedmusic selections, advertisements, news programs, and the like.

With reference to FIG. 3A, a payload channel 40 is generated via theprogramming center 20 to transmit live talk segments 32 and data 42which provides instructions to receivers 14 to playback selected ones oflocally stored content segments. The data 42 preferably comprisesidentifiers for locally stored content segments and progress data. Whengenerating an output signal from the received payload channel 40, areceiver 14 uses the identifiers (e.g., “425”, “007”, “8”, and so on) toaccess and retrieve corresponding content segments from a local storagedevice, as indicated in FIG. 3B. The receiver 14 uses the progress datato determine when to playback the retrieved content segments withrespect to the broadcast live content segments 32 in the payload channel40. For example, the progress data can indicate the current time indexin a content segment at a particular point in time during thetransmission and playback of a payload channel. Accordingly, theprogress data facilitates the generation of an output signal from thereceived payload channel 40 which is perceived by users as being acontinuous composite data stream that was broadcast with retrievedcontent segments therein, as indicated in FIG. 3C.

The advantages of the present invention will now be discussed withreference to FIGS. 4A through 4D. FIGS. 4B and 4D contrast theinstantaneous bandwidth requirements over time of the payload channels30 and 40, respectively, in FIGS. 4A and 4C. As stated previously inconnection with FIG. 2, the payload channel 30 is an exemplary radiobroadcast transmission. As indicated in FIG. 4B, the instantaneousbandwidth requirement varies based on the content segment. Musicalselections 36 (e.g., segments “425”, “007”, “133”, “083”, “350” and“196”) use significantly more bandwidth per content segment than “live”content segments 32 comprising dialogue. Prerecorded advertisements 34generally use more instantaneous bandwidth than the “live” contentsegments 32 but less bandwidth than musical recordings 36. Thus,bandwidth efficiency can be increased if content segments such asmusical recordings 36 can be stored at the receivers 14. Thetransmission bandwidth requirement to provide a musical recording to auser via a receiver 14 is therefore reduced, as evident from FIG. 4D,when a content segment index or identifier and progress data 42 istransmitted in lieu of the corresponding content segment, as shown inFIG. 4C.

FIG. 5 illustrates an exemplary receiver 14 with a local storage device50. The local storage device 50 can be any memory device that can storeinformation in a digital format and can include, but is not limited to,a floppy disc, a hard disk, a compact disc (CD), a digital video disc(DVD), an optical disc, random access memory (RAM), a FLASH memory, adisk pack, digital audio tape (DAT), or other medium for storage andretrieval of digital information. The local storage device 50 can beprovided within a receiver 14 chassis or connected externally thereto.Selected content segments 48 are stored in the local storage device,along with associated index information (e.g., unique identifiers).

With continued reference to FIG. 5, the receiver 14 comprises an antenna52 for receiving a broadcast signal from at least one of the satellites12 and 16 and/or a terrestrial repeater 17. As stated previously, thebroadcast signal can originate from only a terrestrial transmissionsystem. A converter 55 is preferably provided which is operable toperform radio frequency (RF) downconversion, and any demodulation,synchronization, demultiplexing, de-interleaving and decoding functionsperformed as part of the transport layer at a broadcast station in thesystem 10, and described in the afore-mentioned application Ser. No.09/433,862, to obtain the baseband payload channels from the broadcastcomposite data stream. The receiver 14 comprises a controller 60connected to a display 64 and keypad 62 to allow a user to select apayload channel, among other operations. In response to the user programchannel selection, the controller 60 provides control signals to ademultiplexer 58 to select the corresponding payload channel for outputvia a loudspeaker 66 or other output device (e.g., a display ormonitor).

The converter 55 comprises an RF-to-audio converter 54 and anRF-to-control data converter 56 to extract, respectively, the contentsegments 32 and the control data 42 from a selected payload channel 40in the received signal. The content segments 32 are preferably providedto the output device 66 via a signal multiplexer 59 as soon as they arereceived and processed via the converter 55 and demultiplexer 58. Theextracted control data 42 is provided to the controller 60 whichgenerates control signals for the signal multiplexer 59 and the localstorage device 50. The control signals provided to the local storagedevice 50 indicate which of the stored content segments 48 stored in thelocal storage device 50 are to be accessed and retrieved in accordancewith the control data. The control signals provided to the signalmultiplexer 59 from the controller 60 indicate when retrieved contentsegments are to be provided in the output signal in accordance with thecurrent time index provided in the control data 42 for the correspondingretrieved content segment.

The content segments 48 stored in the local storage device 50 can beupdated via any of a number of different methods. For example, abroadcast signal can be provided to the controller 60 for controllingthe storage device 50 to delete selected content segments storedtherein, to replace selected content segments with different segmentstransmitted in the broadcast signal, as well as to add new segmentstransmitted in the broadcast signal. Instructions for updating thestorage device 50 and corresponding content segments can also beprovided via an application provided on a portable storage device, ordownloaded from a terrestrial communication network.

Although the present invention has been described with reference to apreferred embodiment thereof, it will be understood that the inventionis not limited to the details thereof. Various modifications andsubstitutions will occur to those of ordinary skill in the art. All suchsubstitutions are intended to be embraced within the scope of theinvention as defined in the appended claims.

1. A method for generating an output signal at each of a plurality ofreceivers using a broadcast signal transmitted to the plurality ofreceivers in a digital broadcast system comprising the steps of: storingpredefined content segments in a memory device associated with each ofthe plurality of receivers; receiving said broadcast signal at each ofthe plurality of receivers, said broadcast signal comprising segments ofprogram content and segments of control data for reception by theplurality of receivers; accessing and retrieving selected saidpredefined content segments identified by said control data from saidmemory device of at least some of the plurality of receivers; andplaying back the selected said predefined content segments in saidoutput signal in accordance with said control data using at least someof the plurality of receivers; wherein said memory device at each of theplurality of receivers comprises index data with which to identify eachof said predefined content segments stored therein, and said controldata comprises said index data corresponding to the selected saidpredefined content segments, said accessing step comprises the step ofusing said index data in said control data to retrieve said predefinedcontent segments corresponding thereto from said memory device.
 2. Amethod as claimed in claim 1, wherein said broadcast signal comprisescontent segment progress data for providing a time index for playingback one of said predefined content segments associated therewith, saidplaying back step comprising the steps of: playing back live broadcastcontent in said broadcast signal in substantially real-time in saidoutput signal; extracting said index data and corresponding said contentprogress data in said broadcast signal as said broadcast signal isreceived; and inserting the selected said predefined content segmentsamong said segments of program content using said index data and saidcontent progress data to determine when the selected said predefinedcontent segments are to be played back as said broadcast signal isreceived.
 3. A method as claimed in claim 2, wherein playing back saidoutput signal comprises the step of generating an audio output signalusing said live broadcast data and inserting the selected saidpredefined content segments at selected intervals therein in accordancewith said index data and said content progress data.
 4. A method asclaimed in claim 1, further comprising the step of updating saidpredefined content segments in said memory device.
 5. A method asclaimed in claim 4, wherein said updating step comprises the step ofreceiving broadcast content in said broadcast signal for updating saidpredefined content segments.
 6. A method as claimed in claim 4, whereinsaid updating step comprises the step of retrieving program contentstored on a portable storage medium to update said predefined contentsegments in said memory device.
 7. A method for generating an outputsignal at a receiver using a broadcast signal transmitted in a digitalbroadcast system comprising: transmitting a multiplexed broadcast signalvia at least one transmitter, the broadcast signal comprising contentsegments and control data for receivers; receiving the transmittedbroadcast signal; extracting at least portions of said content segmentsand control data from the received broadcast signal; storing predefinedcontent segments, retrieving selected ones of the stored predefinedcontent segments in accordance with said control data in the receivedbroadcast signal, said control data indicating which of said predefinedcontent segments are to be retrieved from the memory and played back inan output signal comprising at least some of the content segmentsextracted from the received broadcast signal.
 8. A broadcast systemcomprising: a broadcast signal transmitted by at least one transmitter,the broadcast signal comprising content segments and control data forreceivers; a plurality of receivers, at least some of the plurality ofreceivers comprising memory for storing predefined content segments, anda controller for controlling the receiver to receive said broadcastsignal, and retrieve selected ones of the stored predefined contentsegments from the memory device in accordance with said control data insaid received broadcast signal, said control data indicating which ofsaid predefined content segments are to be retrieved from the memory andplayed back in an output signal comprising at least some of the contentsegments extracted from the received broadcast signal.
 9. A broadcastsystem as claimed in claim 8, wherein said content segments in saidbroadcast signal are played back substantially in real-time in saidoutput signal.